- Negative correlations between cultivable and active-yet-uncultivable pyrene degraders explain the postponed bioaugmentation
-
Bioaugmentation is an effective approach to remediate soils contaminated by polycyclic aromatic hydrocarbons (PAHs), but suffers from unsatisfactory performance in engineering practices, which is hypothetically explained by the complicated interactions between indigenous microbes and introduced degraders. This study isolated a cultivable pyrene degrader (Sphingomonas sp. YT1005) and an active pyrene degrading consortium (Gp16, Streptomyces, Pseudonocardia, Panacagrimonas, Methylotenera and Nitrospira) by magnetic-nanoparticle mediated isolation (MMI) from soils. Pyrene biodegradation was postponed in bioaugmentation with Sphingomonas sp. YT1005, whilst increased by 30.17% by the active pyrene degrading consortium. Pyrene dioxygenase encoding genes (nidA, nidA3 and PAH-RHDα-GP) were enriched in MMI isolates and positively correlated with pyrene degradation efficiency. Pyrene degradation by Sphingomonas sp. YT1005 only followed the phthalate pathway, whereas both phthalate and salicylate pathways were observed in the active pyrene degrading consortium. The results indicated that the uncultivable pyrene degraders were suitable for bioaugmentation, rather than cultivable Sphingomonas sp. YT1005. The negative correlations between Sphingomonas sp. YT1005 and the active-yet-uncultivable pyrene degraders were the underlying mechanisms of bioaugmentation postpone in engineering practices.
- Jiang, Bo,Chen, Yating,Xing, Yi,Lian, Luning,Shen, Yaoxin,Zhang, Baogang,Zhang, Han,Sun, Guangdong,Li, Junyi,Wang, Xinzi,Zhang, Dayi
-
-
- A visible light driven 3D hierarchical CoTiO3/BiOBr direct Z-scheme heterostructure with enhanced photocatalytic degradation performance
-
A series of novel three-dimensional (3D) CoTiO3/BiOBr (CTBB) hierarchical heterostructures were preparedviaa simple hydrothermal method. In comparison with pure CoTiO3and BiOBr, all the CTBB nanocomposites display enhanced photocatalytic performance toward dye decomposition. Particularly, CTBB-5 reveals the best photocatalytic efficiency for RhB removal with aKof 0.2030 min?1, which is about 50.75 and 3.02-fold higher than that of pure CoTiO3and BiOBr, respectively. The outstanding activity is further demonstrated by MO photodegradation. The dramatically enhanced activity can be attributed to the increased surface area and reduced recombination probability of charge carriers. Furthermore, CTBB-5 exhibits excellent stability after repetitively running four times. The h+and ˙O2?are identified as the dominating reactive species contributing to the oxidation reaction. Finally, a possible Z-scheme charge transfer mechanism is presented and analyzed in detail.
- He, Shiwu,Li, Qiang,Lu, Xiaoxiao,Tian, Zhenfei,Wang, Lijie,Zhang, Jinfeng
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p. 124 - 135
(2021/12/30)
-
- Method for treating 4-AA intermediate waste liquid
-
The invention belongs to the technical field of chemical synthesis, and discloses a method for treating 4-AA intermediate waste liquid. The method comprises the following three steps of: (1) heating N, N-bis (2-ethoxyl) phthalimide and a basic catalyst in an aqueous solution for reflux reaction to prepare a sodium phthalate feed liquid; (2) carrying out reduced pressure distillation on the sodium phthalate feed liquid in the step (1) to obtain ethanolamine, and preparing phthalic acid from residual residues through acid regulation; and (3) introducing ammonia gas or adding ammonia water into a reaction kettle containing the phthalic acid so as to perform heating reaction, performing cooling after the reaction is finished, adding water for washing, crystallizing, filtering and drying to obtain the phthalimide. According to the method disclosed by the invention, the byproduct hazardous wastes in the deprotection step of the enzymic method 4-AA are converted into the initial raw material of the enzymic method 4-AA, so that the hazardous wastes are turned into wealth, the raw material cost is effectively reduced, the storage, transportation and treatment expenses of the hazardous wastes are also effectively reduced, and the method has remarkable economic benefits and environmental benefits.
- -
-
-
- Synthesis of New Dialkyl 2,2′-[Carbonyl bis (azanediyl)]dibenzoates via Curtius Rearrangement
-
The 2-(alkylcarbonyl)benzoic acids obtained by esterification of phthalic anhydride are converted into azide derivatives: alkyl 2-[(azidocarbonyl)amino]benzoates and to ureas: dialkyl 2,2′-[carbonyl bis (azanediyl)]dibenzoates. These transformations were carried out using classical Curtius rearrangement conditions in the presence of diphenylphosphoryl azide (DPPA) in a basic medium, followed by hydrolysis. Subsequently, a final condensation reaction of these urea derivatives enabled us to obtain, for the first time, the new alkyl derivatives, alkyl 2-[2,4-dioxo-1,2-dihydroquinazolin-3(4 H)-yl]benzoates. All the new compounds obtained in satisfactory yields were characterized by 1H and 13C NMR, and by X-ray crystallographic analysis.
- Yassine, Hasna,Bouali, Jamila,Oumessaoud, Asmaa,Ourhzif, El Mahdi,Hamri, Salha,Hafid, Abderrafia,Khouili, Mostafa,Pujol, Maria Dolors
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p. 1971 - 1979
(2021/01/21)
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- Chemical Modifications Induced by Phthalic Anhydride, a Respiratory Sensitizer, in Reconstructed Human Epidermis: A Combined HRMAS NMR and LC-MS/MS Proteomic Approach
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Chemical skin and respiratory allergies are becoming a major health problem. To date our knowledge on the process of protein haptenation is still limited and mainly derived from studies performed in solution using model nucleophiles. In order to better understand chemical interactions between chemical allergens and the skin, we have investigated the reactivity of phthalic anhydride 1 (PA), a chemical respiratory sensitizer, toward reconstructed human epidermis (RHE). This study was performed using a new approach combining HRMAS NMR to investigate the in situ chemical reactivity and LC-MS/MS to identify modified epidermal proteins. In RHE, the reaction of PA appeared to be quite fast and the major product formed was phthalic acid. Two amide type adducts on lysine residues were observed and after 8h of incubation, we also observed the formation of an imide type cyclized adducts with lysine. In parallel, RHE samples topically exposed to phthalic anhydride (13C)-1 were analyzed using the shotgun proteomics method. Thus, 948 different proteins were extracted and identified, 135 of which being modified by PA, i.e., 14.2% of the extracted proteome. A total of 211 amino acids were modified by PA and validated by fragmentation spectra. We thus identified 154 modified lysines, 22 modified histidines, 30 modified tyrosines, and 5 modified arginines. The rate of modified residues, as a proportion of the total number of modifiable nucleophilic residues in RHE, was rather low (1%). At the protein level, modified proteins were mainly type I and type II keratins and other proteins which are abundant in the epidermis such as protein S100A, Caspase 14, annexin A2, serpin B3, fatty-acid binding protein 5, histone H2, H3, H4, etc. However, the most modified protein, mainly on histidine residues, was filaggrin, a protein that is of low abundance (0.0266 mol %) and rich in histidine.
- Khong, Minh-Thuong,Berl, Valérie,Kuhn, Lauriane,Hammann, Philippe,Lepoittevin, Jean-Pierre
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p. 2087 - 2099
(2021/08/30)
-
- Cleavage of Carboxylic Esters by Aluminum and Iodine
-
A one-pot procedure for deprotecting carboxylic esters under nonhydrolytic conditions is described. Typical alkyl carboxylates are readily deblocked to the carboxylic acids by the action of aluminum powder and iodine in anhydrous acetonitrile. Cleavage of lactones affords the corresponding ω-iodoalkylcarboxylic acids. Aryl acetylates undergo deacetylation with the participation of the neighboring group. This method enables the selective cleavage of alkyl carboxylic esters in the presence of aryl esters.
- Sang, Dayong,Yue, Huaxin,Fu, Yang,Tian, Juan
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p. 4254 - 4261
(2021/03/09)
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- Oxidative Degradation of Azo Dyes in Aqueous Solution by Water-Soluble Iron Porphyrin Catalyst
-
Textile and food industries produce a significant volume of effluents containing azo dyes and other pollutants. These effluents are serious environmental threats, and new methods for their treatment and for the degradation of azo dyes are thus attracting much attention. The current study deals with the oxidative degradation of azo dyes by meso-tetrakis(1-methylpyridinium-4-yl)prophyrinatoiron(III), [FeIII(tmpyp)], and meta-chloroperoxy benzoic acid (m-CPBA) in aqueous solution at room temperature. The catalytic degradation of azo dyes was investigated by using rapid-scan stopped-flow spectrophotometry as a function of solution pH, [catalyst], [m-CPBA], [dye] and [surfactants]. To obtain mechanistic insight, the reaction between [FeIII(tmpyp)] and m-CPBA was also studied in aqueous solution in absence of azo dyes. Spectral analyses and kinetic data show that [FeIII(tmpyp)] is transformed into the transient intermediate [FeIV(O)(tmpyp)].+ (a compound I analog) within 20–30 ms followed by the formation of relatively stable [FeIV(O)(tmpyp)] (a compound II analog). Batch experiments reveal that the dye degradation rate is influenced by the solution pH and the concentrations of [FeIII(tmpyp)], m-CPBA, dye, and surfactants. On the basis of the kinetic and spectroscopic data, a mechanistic scheme for the dye degradation reaction and a steady-state rate equation are proposed. The products resulting from oxidative degradation of the azo dye amaranth have been analyzed by HPLC-UV-HRMS.
- Saha, Tapan Kumar,Frauendorf, Holm,Meyer, Franc
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p. 2870 - 2881
(2021/07/14)
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- A Janus-type Heterogeneous Surfactant for Adipic Acid Synthesis
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A highly water-dispersible heterogeneous Br?nsted acid surfactant was prepared by synthesis of a bi-functional anisotropic Janus-type material. The catalyst comprises ionic functionalities on one side and propyl-SO3H groups on the other. The novel material was investigated as a green substitute of a homogeneous acidic phase transfer catalyst (PTC). The activity of the catalyst was investigated for the aqueous-phase oxidation of cyclohexene to adipic acid with 30 % hydrogen peroxide even in a decagram-scale. It can also be used for the synthesis of some other carboxylic acid derivatives as well as diethyl phthalate.
- Antonyuk, Sergiy,Breuninger, Paul,Ernst, Stefan,Thiel, Werner R.,Vafaeezadeh, Majid,Wilhelm, Christian
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- Coordination among Bond Formation/Cleavage in a Bifunctional-Catalyzed Fast Amide Hydrolysis: Evidence for an Optimized Intramolecular N-Protonation Event
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A density functional theory (DFT) computational analysis, using the ωB97X-D functional, of a rapid amide cleavage in 2-carboxyphthalanilic acid (2CPA), where the amide group is flanked by two catalytic carboxyls, reveals key mechanistic information: (a) General base catalysis by a carboxylate coupled to general acid catalysis by a carboxyl is not operative. (b) Nucleophilic attack by a carboxylate on the amide carbonyl coupled to general acid catalysis at the amide oxygen can also be ruled out. (c) A mechanistic pathway that remains viable involves general acid proton delivery to the amide nitrogen by a carboxyl, while the other carboxylate engages in nucleophilic attack upon the amide carbonyl; a substantially unchanged amide carbonyl in the transition state; two concurrent bond-forming events; and a spatiotemporal-base rate acceleration. This mechanism is supported by molecular dynamic simulations which confirm a persistent key intramolecular hydrogen bonding. These theoretical conclusions, although not easily verified by experiment, are consistent with a bell-shaped pH/rate profile but are at odds with hydrolysis mechanisms in the classic literature.
- Affeldt, Ricardo F.,Caramori, Giovanni F.,De Souza, Fábio P. S.,Ferraz, Matheus S.,Menger, Fredric M.,Nome, Faruk,Oliveira, Bruno S.,Scorsin, Leandro,Silveira, Eduardo V.,Souza, Bruno S.
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p. 4663 - 4671
(2020/05/01)
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- P-aminomethyl benzoic acid and preparation method thereof
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The invention discloses p-aminomethyl benzoic acid and a preparation method thereof. The method comprises the following steps: hydrolyzing phthalic anhydride as a raw material under an alkaline condition to enable the anhydride structure of phthalic anhydride to be subjected to ring opening to obtain an intermediate 1; performing decarboxylation reaction on the intermediate 1 under the condition that high-temperature liquid water is used as a reaction medium to obtain an intermediate 2; converting original binary acid of the intermediate 1 into monobasic acid, and enabling the intermediate 2 to react with a saturated monochloromethane diethyl ether solution by taking diethyl ether as a solvent under the catalytic action of aluminum chloride to obtain an intermediates 3; and carrying out bromine substitution reaction on the intermediate 3 and N-bromosuccinimide, and carrying out ammoniation reaction under the action of triethylamine and potassium carbonate. The yield of p-aminomethyl benzoic acid prepared by the preparation method of p-aminomethyl benzoic acid is high, and compared with an existing preparation method, most of the used raw materials are low-price raw materials, cyanogroups with high toxicity are not introduced, and the production cost of tranexamic acid is greatly reduced.
- -
-
Paragraph 0011; 0033-0035; 0039-0041; 0045-0047
(2020/09/09)
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- Cobalt-Catalyzed Acceptorless Dehydrogenation of Alcohols to Carboxylate Salts and Hydrogen
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The facile oxidation of alcohols to carboxylate salts and H2 is achieved using a simple and readily accessible cobalt pincer catalyst (NNNHtBuCoBr2). The reaction follows an acceptorless dehydrogenation pathway and displays good functional group tolerance. The amine-amide metal-ligand cooperation in cobalt catalyst is suggested to facilitate this transformation. The mechanistic studies indicate that in-situ-formed aldehydes react with a base through a Cannizzaro-type pathway, resulting in potassium hemiacetolate, which further undergoes catalytic dehydrogenation to provide the carboxylate salts and H2
- Gunanathan, Chidambaram,Kishore, Jugal,Pattanaik, Sandip,Pradhan, Deepak Ranjan
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supporting information
(2020/03/03)
-
- Method for directly oxidizing benzylic C-H bond to ketone or acid
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The invention discloses a method for directly oxidizing benzylic C-H bonds into ketone or acid. A target product is obtained through an oxidation reaction with a compound containing benzylic C-H bondsas a substrate, trichloroisocyanuric acid as an oxidizing agent and sodium bromide and tetramethyl piperidine nitrogen oxide as catalysts. The oxidizing agent and the catalysts are cheap and easy toobtain, transport and store; the oxidative catalysis effect is good; the reaction condition is mild, the requirement and effect of harsh reaction conditions on equipment are avoided, and the method issuitable for industrial mass production. The use of a large quantity of heavy metal salts is avoided, and environmental pollution is further avoided.
- -
-
Paragraph 0034-0037
(2020/12/14)
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- Site-Specific C(sp3)–H Aminations of Imidates and Amidines Enabled by Covalently Tethered Distonic Radical Anions
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The utilization of N-centered radicals to synthesize nitrogen-containing compounds has attracted considerable attention recently, due to their powerful reactivities and the concomitant construction of C?N bonds. However, the generation and control of N-centered radicals remain particularly challenging. We report a tethering strategy using SOMO-HOMO-converted distonic radical anions for the site-specific aminations of imidates and amidines with aid of the non-covalent interaction. This reaction features a remarkably broad substrate scope and also enables the late-stage functionalization of bioactive molecules. Furthermore, the reaction mechanism is thoroughly investigated through kinetic studies, Raman spectroscopy, electron paramagnetic resonance spectroscopy, and density functional theory calculations, revealing that the aminations likely involve direct homolytic cleavage of N?H bonds and subsequently controllable 1,5 or 1,6 hydrogen atom transfer.
- Fang, Yuanding,Fu, Kang,Shi, Lei,Zhao, Rong,Zhou, Jia
-
supporting information
p. 20682 - 20690
(2020/09/07)
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- N-Doped carbon nanofibers derived from bacterial cellulose as an excellent metal-free catalyst for selective oxidation of arylalkanes
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N-Doped carbon nanofibers derived from one-step pyrolysis of low-cost bacterial cellulose with the assistance of urea were reported. Owing to their interconnected nanofibrous structure and high specific surface area as well as high N doping, they exhibited excellent catalytic performance for selective oxidation of arylalkanes even with O2 as an oxidant in aqueous solution.
- Huang, Runkun,Cao, Changyan,Liu, Jian,Sun, Dongping,Song, Weiguo
-
supporting information
p. 1935 - 1938
(2019/05/02)
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- The sustainable room temperature conversion of: P -xylene to terephthalic acid using ozone and UV irradiation
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Current industrial processes utilize Co/Mn bromides as catalysts to catalyze the oxidative conversion of para-xylene to terephthalic acid (TA) in acetic acid at high temperatures (>200 °C, air, 15-30 atm.). The decomposition of metallo-catalysts and solvents at high temperatures as well as a subsequent hydropurification process releases thousands of millions of tons of wastewater, global warming gas (CO2) and ozone depleting gas (CH3Br) into the global environment per year, causing global warming, ozone depletion, dramatic climate change, huge economic losses, and many other environmental problems. Herein, we report an alternative sustainable process with low energy demand for the room temperature oxidative conversion of p-xylene to terephthalic acid, with 96% TA yield and 98% selectivity, via ozone treatment and concurrent UV irradiation and without the generation and release of greenhouse gas (CO2), ozone depleting gas (CH3Br), and wastewater, or the need for a high energy-demand hydropurification process. The reaction mechanism involves the singlet O(1D)- and hydroxyl radical-mediated selective C-H functionalization of p-xylene.
- Hwang, Kuo Chu,Sagadevan, Arunachalam,Kundu, Pradip
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p. 6082 - 6088
(2019/11/20)
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- Selective Synthesis in Microdroplets of 2-Phenyl-2,3-dihydrophthalazine-1,4-dione from Phenyl Hydrazine with Phthalic Anhydride or Phthalic Acid
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Pyridazine derivatives are privileged structures because of their potential biological and optical properties. Traditional synthetic methods usually require acid or base as a catalyst under reflux conditions with reaction times ranging from hours to a few days or require microwave assistance to induce the reaction. Herein, this work presents the accelerated synthesis of a pyridazine derivative, 2-phenyl-2,3-dihydrophthalazine-1,4-dione (PDHP), in electrosprayed microdroplets containing an equimolar mixture of phenyl hydrazine and phthalic anhydride or phthalic acid. This reaction occurred on the submillisecond timescale with good yield (over 90 % with the choice of solvent) without using an external catalyst at room temperature. In sharp contrast to the bulk reaction of obtaining a mixture of two products, the reaction in confined microdroplets yields only the important six-membered heterocyclic product PDHP. Results indicated that surface reactions in microdroplets with low pH values cause selectivity, acceleration, and high yields.
- Gao, Dan,Jin, Feng,Yan, Xin,Zare, Richard N.
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supporting information
p. 1466 - 1471
(2019/01/04)
-
- Method of preparing phthalic acid by polyacid catalyzed oxidation
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The invention relates to a method of preparing phthalic acid by Anderson polyacid catalyzed oxidation. The method comprises the following steps: adding phthalic acid, an Anderson polyacid catalyst, anadditive and a solvent into a reactor; magnetically stirring the components in an oxygen atmosphere to react; and fully stirring the mixture for 12-24 hours at a reaction temperature of 100-220 DEG Cto obtain a needed product. The method avoids a reaction condition of using a high corrosion, high toxic and easily drug manufacturing reagent at a high temperature and a high pressure in a conventional synthesizing method and adopts the Anderson polyacid as a catalyst, so that the method has extremely high reaction activity and the needed reaction is mild in condition and environment-friendly. The method is high in specific selectivity, recycable and suitable for industrial production. Hydrogen peroxide, air or oxygen is taken as an oxidizing agent, so that the manufacturing cost and three wastes are reduced, and the environmental pressure is alleviated. The method also has the characteristics of being easy to control and produce industrially.
- -
-
Paragraph 0046-0051
(2019/07/08)
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- Comparative study on degradation of propranolol and formation of oxidation products by UV/H2O2 and UV/persulfate (PDS)
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The frequent detection of propranolol, a widely used β-blocker, in wastewater effluents and surface waters has raised serious concern, due to its adverse effects on organisms. UV/hydrogen peroxide (UV/H2O2) and UV/persulfate (UV/PDS) processes are efficient in eliminating propranolol in various waters, but the formation of oxidation products in these processes, as well as the assessment of their toxicity, has not been systematically addressed. In this study, we identified and compared transformation products of propranolol produced by hydroxyl radical (?OH) and sulfate radical (SO4?-). The electrostatic attraction enhances the reaction between SO4?- and the protonated form of propranolol, while ?OH shows non-selectivity toward both protonated and neutral propranolol species. The hydroxylation of propranolol by ?OH occurs at either amine moiety or naphthalene group while SO4?- favors the oxidation of the electron-rich naphthalene group. Further oxidation by ?OH and SO4?- results in ring-opening products. Bicarbonate and chloride exert no effect on propranolol degradation. The generation of CO3?- and Cl-containing radicals is favorable to oxidizing naphthalene group. The acute toxicity assay of Vibrio fischeri suggests that SO4?- generates more toxic products than ?OH, while CO3?- and Cl-containing radicals produce similar toxicity as SO4?-. High concentrations of bicarbonate in UV/H2O2 increase the toxicity of treated solution.
- Yang, Yi,Cao, Ying,Jiang, Jin,Lu, Xinglin,Ma, Jun,Pang, Suyan,Li, Juan,Liu, Yongze,Zhou, Yang,Guan, Chaoting
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p. 543 - 552
(2019/01/05)
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- Synthesis of Chiral Polyhydroxylated Benzimidazoles by a Tandem Radical Fragmentation/Cyclization Reaction: A Straight Avenue to Fused Aromatic-Carbohydrate Hybrids
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The synthesis of benzimidazole-fused iminosugars through a tandem β-fragmentation-intramolecular cyclization reaction is described. The use of the benzimidazole ring as the internal nucleophile and the use of phenyliodosophthalate (PhI(Phth)), a new metal-free and low toxic hypervalent iodine reagent, are the most remarkable novelties of this synthetic strategy. With this approach, we have demonstrated the usefulness of the fragmentation of anomeric alkoxyl radicals promoted by the PhI(Phth)/I2 system for the preparation of new compounds with potential interest for both medicinal and synthetic chemists.
- André-Joyaux, Emy,Santana, Andrés G.,González, Concepción C.
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p. 506 - 515
(2019/01/24)
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- Cobalt-catalyzed carbonylative synthesis of phthalimides from n-(pyridin-2-ylmethyl)benzamides with tfben as the co source
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A cobalt-catalyzed direct carbonylative synthesis of phthalimide motifs from N-(pyridin-2-ylmethyl)benzamides has been developed. Various phthalimide derivatives were obtained in moderate to excellent yields (up to 98percent) by using 2-picolylamine as an efficient directing group and benzene-1,3,5-triyl triformate (TFBen) as a convenient CO surrogate.
- Fu, Lu-Yang,Wu, Xiao-Feng,Ying, Jun
-
-
- Catalytic Oxidative Cracking of Benzene Rings in Water
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Efficient degradation of harmful benzene rings in water is indispensable for achieving a clean water environment. We report herein unprecedented catalytic oxidative benzene cracking (OBC) in water using a ruthenium(II)-aqua complex having an N-heterocyclic carbene ligand as a catalyst and a cerium(IV) salt as a sacrificial oxidant under mild conditions. The OBC reactions produced carboxylic acids such as formic acid, which can be converted to dihydrogen directly from the OBC solution using a rhodium(III) catalyst with adjustment of the solution pH to 3.3. The OBC reactions can be applied to monosubstituted benzene derivatives such as ethylbenzene, chlorobenzene, and benzoic acid. Initial rates of the OBC reactions showed a linear relationship in the Hammett plot with a negative slope, indicating the electrophilicity of a Ru(III)-oxyl complex as the reactive species in the catalytic OBC reaction. Also, we discuss a plausible mechanism of the catalytic OBC reactions based on the kinetic analysis and the product stoichiometry for the OBC reaction of nonvolatile sodium m-xylene sulfonate. The addition of an electrophilic radical to the aromatic ring to form arene oxide/oxepin is proposed as the initial step of the OBC reaction.
- Shimoyama, Yoshihiro,Ishizuka, Tomoya,Kotani, Hiroaki,Kojima, Takahiko
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p. 671 - 678
(2019/01/08)
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- Efficient and Recyclable RuCl3 ? 3H2O Catalyst Modified with Ionic Diphosphine for the Alkoxycarbonylation of Aryl Halides
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A series of ionic (mono-/di-)phosphines (L2, L4, and L6) with structural similarity and their corresponding neutral counterparts (L1, L3, and L5) were applied to modulate the catalytic performance of RuCl3 ? 3H2O. With the involvement of the ionic diphosphine (L4), in which the two phosphino-fragments were linked by butylene group, RuCl3 ? 3H2O with advantages of low cost, robustness, and good availability was found to be an efficient and recyclable catalyst for the alkoxycarbonylation of aryl halides. The L4-based RuCl3 ? 3H2O system corresponded to the best conversion of PhI (96 %) along with 99 % selectivity to the target product of methyl benzoate as well as the good generality to alkoxycarbonylation of different aryl halides (ArX, X=I and Br) with alcohols MeOH, EtOH, i-PrOH and n-BuOH. The electronic and steric effects of the applied phosphines, which were analyzed by the 31P NMR for 1J31P-77Se1J measurement and single-crystal X-ray diffraction, were carefully co-related to the performance RuCl3 ? 3H2O catalyst. In addition, the L4-based RuCl3 ? 3H2O system could be recycled successfully for at least eight runs in the ionic liquid [Bmim]PF6.
- Zhou, Qing,Liu, Lei,Guo, Wen-Di,Liang, Wen-Yu,Lu, Yong,Liu, Ye
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p. 166 - 172
(2019/02/01)
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- Selective oxidation of benzyl alcohol to benzaldehyde, 1-phenylethanol to acetophenone and fluorene to fluorenol catalysed by iron (II) complexes supported by pincer-type ligands: Studies on rapid degradation of organic dyes
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Hexacoordinated non-heme iron complexes [FeII(L1)2](ClO4)2 (1) and [FeII(L2)2](PF6)2 (2) have been synthesized using ligands L1?=?(E)-2-chloro-6-(2-(pyridin-2ylmethylene) hydrazinyl)pyridine and L2?=?(E)-2-chloro-6-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl) pyridine]. These complexes are highly active non-heme iron catalysts to catalyze the C (sp3)?H bonds of alkanes. These iron complexes have been characterized using ESI?MS analysis and molecular structures were determined by X-ray crystallography. ESI???MS analysis also helped to understand the generation of intermediate species like FeIII?OOH and FeIV=O. DFT and TD?DFT calculations revealed that the oxidation reactions were performed through high-valent iron center and a probable reaction mechanism was proposed. These complexes were also utilized for the degradation of orange II and methylene blue dyes.
- Singh, Ovender,Gupta, Priyanka,Singh, Anshu,Maji, Ankur,Singh, Udai P.,Ghosh, Kaushik
-
-
- Controlled Photocatalytic Hydrocarbon Oxidation by Uranyl Complexes
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Controlled, photocatalytic C?H bond activations are key reactions in the toolkits of the modern synthetic chemist. While it is known that the uranyl(VI) ion, [UVIO2]2+, the environmentally dominant form of uranium, is photoactive, most literature examines its luminescent properties, neglecting its potential synthetic utility for photocatalytic C?H bond cleavage. Here, we synthesise and fully characterise an air-stable and hydrocarbon-soluble uranyl phenanthroline complex, [UVIO2(NO3)2(Ph2phen)], UPh2phen, and demonstrate that it can catalytically abstract hydrogen atoms from a variety of organic substrates under visible light irradiation. We show that the commercially available parent complex, uranyl nitrate ([UVIO2(NO3)2(OH2)2]?4H2O; UNO3), is also competent, but from electronic spectroscopy we attribute the higher rates and selectivity of UPh2phen to ligand-mediated electronic effects. Ketones are selectively formed over other oxygenated products (alcohols, etc.), and the catalytic oxidation of substrates containing a benzylic C?H position is particularly improved for UPh2phen. We also show uranyl-mediated photocatalytic C?C bond cleavage in a model lignin compound for the first time.
- Arnold, Polly L.,Purkis, Jamie M.,Rutkauskaite, Ryte,Kovacs, Daniel,Love, Jason B.,Austin, Jonathan
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p. 3786 - 3790
(2019/03/07)
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- Synthesis method of chiral compound R-(+)-2-methyl-3-phenyl-1-propyl alcohol
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The invention discloses a synthesis method of a chiral compound R-(+)-2-methyl-3-phenyl-1-propyl alcohol. The synthesis method comprises the following steps: taking alpha-methyl cinnamaldehyde as a raw material and performing a catalytic hydrogenation reaction on the alpha-methyl cinnamaldehyde to obtain (plus or minus)-2-methyl-3-phenyl-1-propyl alcohol; performing an esterification reaction on the (plus or minus)-2-methyl-3-phenyl-1-propyl alcohol and phthalic anhydride to form monoester; performing an acid-base reaction on the monoester and S-(-)-alpha-phenylethylamine to form salt; separating and purifying a single chiral isomer in the salt through crystallization and recrystallization; performing a hydrolysis reaction to obtain R-(+)-2-methyl-3-phenyl-1-propyl alcohol and a hydrolysisby-product; and finally, removing the hydrolysis by-product through separation and purification to obtain the R-(+)-2-methyl-3-phenyl-1-propyl alcohol.
- -
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Paragraph 0019; 0027-0029; 0030; 0038-0040; 0041; 0049-0051
(2019/04/04)
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- Automated on-line monitoring of the TiO2-based photocatalytic degradation of dimethyl phthalate and diethyl phthalate
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A fully automated on-line system for monitoring the TiO2-based photocatalytic degradation of dimethyl phthalate (DMP) and diethyl phthalate (DEP) using sequential injection analysis (SIA) coupled to liquid chromatography (LC) with UV detection was proposed. The effects of the type of catalyst (sol-gel, Degussa P25 and Hombikat), the amount of catalyst (0.5, 1.0 and 1.5 g L-1), and the solution pH (4, 7 and 10) were evaluated through a three-level fractional factorial design (FFD) to verify the influence of the factors on the response variable (degradation efficiency, %). As a result of FFD evaluation, the main factor that influences the process is the type of catalyst. Degradation percentages close to 100% under UV-vis radiation were reached using the two commercial TiO2 materials, which present mixed phases (anatase/rutile), Degussa P25 (82%/18%) and Hombikat (76%/24%). 60% degradation was obtained using the laboratory-made pure anatase crystalline TiO2 phase. The pH and amount of catalyst showed minimum significant effect on the degradation efficiencies of DMP and DEP. Greater degradation efficiency was achieved using Degussa P25 at pH 10 with 1.5 g L-1 catalyst dosage. Under these conditions, complete degradation and 92% mineralization were achieved after 300 min of reaction. Additionally, a drastic decrease in the concentration of BOD5 and COD was observed, which results in significant enhancement of their biodegradability obtaining a BOD5/COD index of 0.66 after the photocatalytic treatment. The main intermediate products found were dimethyl 4-hydroxyphthalate, 4-hydroxy-diethyl phthalate, phthalic acid and phthalic anhydride indicating that the photocatalytic degradation pathway involved the hydrolysis reaction of the aliphatic chain and hydroxylation of the aromatic ring, obtaining products with lower toxicity than the initial molecules.
- Salazar-Beltrán, Daniel,Hinojosa-Reyes, Laura,Maya-Alejandro, Fernando,Turnes-Palomino, Gemma,Palomino-Cabello, Carlos,Hernández-Ramírez, Aracely,Guzmán-Mar, Jorge Luis
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p. 863 - 870
(2019/04/17)
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- Integrated photocatalytic-biological treatment of triazine-containing pollutants
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The degradation of triazine-containing pollutants including simazine, Irgarol 1051 and Reactive Brilliant Red K-2G (K-2G) by photocatalytic treatment was investigated. The effects of titanium dioxide (TiO2) concentration, initial pH of reaction mixture, irradiation time and ultraviolet (UV) intensity on photocatalytic treatment efficiency were examined. Complete decolorization of K-2G was observed at 60 min photodegradation while only 15 min were required to completely degrade simazine and Irgarol 1051 under respective optimized conditions. High-performance liquid chromatography (HPLC), gas chromatography/mass spectrometry (GC/MS) and ion chromatography (IC) were employed to identify the photocatalytic degradation intermediates and products. Dealkylated intermediates of simazine, deisopropylatrazine and deethyldeisopropylatrazine, and Irgarol 1051 were detected by GC/MS in the initial phase of degradation. Complete mineralization could not be achieved for all triazine-containing pollutants even after prolonged (>72 h) UV irradiation due to the presence of a photocatalysis-resistant end product, cyanuric acid (CA). The toxicities of different compounds before and after photocatalytic treatment were also monitored by three bioassays. To further treat the photocatalysis-resistant end product, a CA-degrading bacterium was isolated from polluted marine sediment and further identified as Klebsiella pneumoniae by comparing the substrate utilization pattern (Biolog microplate), fatty acid composition and 16S rRNA gene sequencing. K. pneumoniae efficiently utilized CA from 1 to 2000 mg/L as a good nitrogen source and complete mineralization of CA was observed within 24 h of incubation. This study demonstrates that the biodegradability of triazine-containing pollutants was significantly improved by the photocatalytic pre-treatment, and this proposed photocatalytic-biological integrated system can effectively treat various classes of triazine-containing pollutants.
- Chan, Cho Yin,Chan, Ho Shing,Wong, Po Keung
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p. 371 - 380
(2019/02/07)
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- Synergetic effects of graphene-CoPc/silk fibroin three-dimensional porous composites as catalysts for acid red G degradation
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The disposal of dye wastewater is one of the hotspots of scientific research. Upon combining the ability of graphene to accelerate the hydroxyl radical generation with the Fenton system, it has shown a faster degradation rate and can be recycled, showing greater degradation efficiency than the traditional dye treatment method. Herein, a catalytic system based on the regenerated silk fibroin (SF) gel integrated with cobalt tetraaminophthalocyanine (CoTAPc)-grafted-reduced graphene oxide (RGO) sheets were fabricated, and its catalytic activity was assessed via the degradation of acid red G (ARG) at varying catalyst and H2O2 dosages, pH values, and temperatures. The results revealed that the three-dimensional (3D) porous RGO-CoTAPc/SF gel exhibited a much stronger catalytic behavior than the other arbitrary components due to its high surface area and synergetic hydroxyl radical generation efficiency, with the dye removal ratio by RGO-CoTAPc/SF being higher in an acidic medium than in an alkaline medium. It also increases with the increase in temperature and RGO-CoTAPc/SF and H2O2 dosages. Further, the catalytic oxidation process of ARG was determined, and the possible degradation mechanism of ARG has been discussed. Our results suggest that the composite materials with high catalytic activity can provide a reference for future Fenton-like catalytic systems.
- Ma, Hui,Zhang, Huanxia,Tong, Mingqiong,Cao, Jianda,Wu, Wen
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p. 24751 - 24759
(2019/08/22)
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- Method of co-producing methyl benzoic acid, methylbenzoyl chloride and phthaloyl dichloride
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The invention discloses a method of co-producing methyl benzoic acid, methylbenzoyl chloride and phthaloyl dichloride. The method comprises the following steps: (1) continuously introducing xylene, acatalyst and oxygen-containing gas into an oxidizing reactor to react to obtain an oxidized reaction solution; (2) rectifying and separating the oxidized reaction solution to obtain a low-boiling-point component and an initial evaporative tower bottom; (3) rectifying the initial evaporative tower bottom to obtain a methyl benzoic acid product and a tower bottom; (4) carrying out an acylating chlorination reaction on the tower bottom and an acylating chlorination reagent to obtain an acyl chloride reaction solution; and (5) rectifying and separating the acyl chloride reaction solution to separately obtain methylbenzoyl chloride and phthaloyl dichloride products. The method provided by the invention has the advantages of being simple in process, small in equipment investment, green and environment-friendly and good in comprehensive economical benefit.
- -
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Paragraph 0178; 0179; 0183-0185; 0196; 0198
(2018/06/16)
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- Dry Chemistry of Ferrate(VI): A Solvent-Free Mechanochemical Way for Versatile Green Oxidation
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The +6 oxidation state of iron generally exists in the form of ferrate(VI) with high redox potential and environmentally friendly nature. Although ferrate(VI) has been known for over a century, its chemistry is still limited to the solvent-based reactions that suffers from the insolubility/instability of this oxidant and the environmental issues caused by hazardous solvents. Herein, we explore the solvent-free reactivity of ferrate(VI) under mechanical milling, revealing that its strong oxidizing power is accessible in the “dry” solid state towards a broad variety of substrates, for example, aromatic alcohols/aldehydes and carbon nanotubes. More significantly, solvent-free mechanochemistry also reshapes the oxidizing ability of ferrate(VI) due to the underlying solvent-free effect and the promotive mechanical actions. This study opens up a new chemistry of ferrate(VI) with promising application in green oxidative transformation of both organic and inorganic substrates.
- Zhang, Zhao-Yang,Ji, Deyang,Mao, Wenting,Cui, Yu,Wang, Qing,Han, Lu,Zhong, Hongliang,Wei, Zhongming,Zhao, Yixin,N?rgaard, Kasper,Li, Tao
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supporting information
p. 10949 - 10953
(2018/08/01)
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- Oxidation of Polynuclear Aromatic Hydrocarbons using Ruthenium-Ion-Catalyzed Oxidation: The Role of Aromatic Ring Number in Reaction Kinetics and Product Distribution
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Oxidation of aromatic hydrocarbons with differing numbers of fused aromatic rings (2–5), have been studied in two solvent environments (monophasic and biphasic) using ruthenium-ion-catalyzed oxidation (RICO). RICO reduces the aromaticity of the polyaromatic core of the molecule in a controlled manner by selective oxidative ring opening. Moreover, the nature of the solvent system determines the product type and distribution, for molecules with more than two aromatic rings. Competitive oxidation between substrates with different numbers of aromatic rings has been studied in detail. It was found that the rate of polyaromatic hydrocarbon oxidation increases with the number of fused aromatic rings. A similar trend was also identified for alkylated aromatic hydrocarbons. The proof-of-concept investigation provides new insight into selective oxidation chemistry for upgrading of polyaromatic molecules.
- Nowicka, Ewa,Clarke, Tomos J.,Sankar, Meenakshisundaram,Jenkins, Robert L.,Knight, David W.,Golunski, Stanislaw,Hutchings, Graham J.,Willock, David J.,Francisco, Manuel,Taylor, Stuart H.
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p. 655 - 662
(2018/01/26)
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- Selective Synthesis of Aryl Nitriles and 3-Imino-1-oxoisoindolines via Nickel-Promoted C(sp2)-H Cyanations
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An efficient nickel-promoted selective monocyanation of benzamides with TMSCN via 8-aminoquinoline directed ortho C-H activation has been developed. Varieties of functionalized ortho-cyanated (hetero)aryl nitriles can be selectively synthesized in moderate to good yields. These cyanation products can be easily transformed into various 3-imino-1-oxoisoindolines in a one-pot procedure. The mild reaction conditions, use of cheap and commercially available reagents, wide functional group tolerance, and operational convenience make this protocol practical to the synthetic community.
- Yu, Lin,Chen, Xiang,Song, Ze-Nan,Liu, Da,Hu, Liang,Yu, Yongqi,Tan, Ze,Gui, Qingwen
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supporting information
p. 3206 - 3210
(2018/06/11)
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- Earth-Abundant Mixed-Metal Catalysts for Hydrocarbon Oxygenation
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The oxygenation of aliphatic and aromatic hydrocarbons using earth-abundant Fe and Cu catalysts and "green" oxidants such as hydrogen peroxide is becoming increasingly important to atom-economical chemical processing. In light of this, we describe that dinuclear CuII complexes of pyrrolic Schiff-base macrocycles, in combination with ferric chloride (FeCl3), catalyze the oxygenation of π-activated benzylic substrates with hydroperoxide oxidants at room temperature and low loadings, representing a novel design in oxidation catalysis. Mass spectrometry and extended X-ray absorption fine structure analysis indicate that a cooperative action between CuII and FeIII occurs, most likely because of the interaction of FeCl3 or FeCl4- with the dinuclear CuII macrocycle. Voltammetric measurements highlight a modulation of both CuII and FeIII redox potentials in this adduct, but electron paramagnetic resonance spectroscopy indicates that any Cu-Fe intermetallic interaction is weak. High ketone/alcohol product ratios, a small reaction constant (Hammett analysis), and small kinetic isotope effect for H-atom abstraction point toward a free-radical reaction. However, the lack of reactivity with cyclohexane, oxidation of 9,10-dihydroanthracene, oxygenation by the hydroperoxide MPPH (radical mechanistic probe), and oxygenation in dinitrogen-purge experiments indicate a metal-based reaction. Through detailed reaction monitoring and associated kinetic modeling, a network of oxidation pathways is proposed that includes "well-disguised" radical chemistry via the formation of metal-associated radical intermediates.
- Pankhurst, James R.,Curcio, Massimiliano,Sproules, Stephen,Lloyd-Jones, Guy C.,Love, Jason B.
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supporting information
p. 5915 - 5928
(2018/05/28)
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- Selective and facile synthesis of α,β-unsaturated nitriles and amides with N-hydroxyphthalimide as the nitrogen source
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The direct conversion of α,β-unsaturated aldehydes to corresponding nitriles promoted by Pd(OAc)2 and phthalic acid which was hydrolyzed from N-hydroxyphthalimide (NHPI) has been disclosed. Additionally, it was found that when water was used as the solvent, α,β-unsaturated amides was obtained as the main products in good to excellent yields. It was first reported that NHPI was utilized as the nitrogen source to synthesize α,β-unsaturated nitriles and amides from aldehydes. Control experiment demonstrated that aldehydes undergo a process of oximation and dehydration to form nitriles and amides.
- Yan, Yiyan,Xu, Xiaohe,Jie, Xiaokang,Cheng, Jingya,Bai, Renren,Shuai, Qi,Xie, Yuanyuan
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p. 2793 - 2796
(2018/06/25)
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- Efficient Synthesis of Phthalimides via Cobalt-Catalyzed C(sp2)?H Carbonylation of Benzoyl Hydrazides with Carbon Monoxide
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A cobalt-catalyzed C?H carbonylation of benzoyl hydrazides has been developed by using 2-(1-methylhydrazinyl)pyridine as the bidentate directing group. This transformation is mild, efficient, operationally simple, and highly functional-group-tolerant. The protocol has generated a broad range of phthalimide derivatives in good to excellent yields. The ligand moiety can be readily removed through hydrogenolysis. (Figure presented.).
- Qiu, Shuxian,Zhai, Shengxian,Wang, Huifei,Tao, Cheng,Zhao, Hua,Zhai, Hongbin
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p. 3271 - 3276
(2018/08/06)
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- Pd-Catalyzed C(sp2)-H aminocarbonylation using the Langlois reagent as a carbonyl source
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A Pd-catalyzed C(sp2)-H aminocarbonylation of aryl carboxamides assisted by an N,S-bidentate directing group was developed, in which cheap and stable sodium trifluoromethanesulfinate was first utilized as a carbonyl source. The reaction can be applicable to a wide range of carboxamides with good functional group tolerance and afford isoindole-1,3-diones in moderate to good yields.
- Li, Xiao-Fang,Shi, Lin-Feng,Zhang, Xing-Guo,Zhang, Xiao-Hong
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supporting information
p. 6438 - 6442
(2018/09/26)
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- "release and catch" catalysis by tungstate species for the oxidative cleavage of olefins
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The oxidative cleavage of olefins produces valuable carbonyl compounds, and thus, the development of green catalytic methods using H2O2 as an oxidant is highly desired. In this work, we have successfully developed an efficient catalytic system for the oxidative cleavage of olefins and related compounds using H2O2. In the presence of tungstate species supported on zinc-modified tin dioxide (W/Zn-SnO2), the oxidative cleavage of 1-methyl-1-cyclohexene proceeds efficiently through multistep reaction pathways involving oxygenation, hydrolysis, perhydrolysis, and isomerization reactions. In this reaction system, active peroxotungstate species, generated by the reaction of the supported tungstate species with H2O2, are released into the solution during the course of the reaction. At the end of the reaction (after the complete consumption of H2O2), the released tungstate species are re-captured by the support. The W/Zn-SnO2 catalyst can be reused at least nine times for the oxidative cleavage of 1-methyl-1-cyclohexene without loss of catalytic performance and can be applied to the oxidation of various other substrate molecules.
- Yoshimura, Yu,Ogasawara, Yoshiyuki,Suzuki, Kosuke,Yamaguchi, Kazuya,Mizuno, Noritaka
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p. 1662 - 1670
(2017/07/22)
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- Preventing false-negatives in the in vitro skin sensitization testing of acid anhydrides using interleukin-8 release assays
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In vitro safety tests may be used as replacements for animal tests owing to their accuracy and high-throughput performance. However, several in vitro skin sensitization tests produce false-negative results such as acid anhydride. Here, we investigated the relationship between false-negative results of acid anhydride and its hydrolysis by aqueous vehicle. Differences in the pattern of hydrolysis for phthalic anhydride (PAH) due to addition of 1 drop of stock solution of PAH in liquid paraffin (LP) dispersion medium and PAH in DMSO were analyzed in a cell-free system. The results showed that use of LP dispersion medium stabilized the concentration of PAH in water over 5 min by sustained-release, although almost all PAH converted to phthalic acid in water within 5 min using DMSO. Additionally, treatment of THP-1 cells with PAH and phthalic acid using LP dispersion medium for 5 min resulted in a 32-fold increase in IL-8 release for PAH as compared with that in the vehicle control. In contrast, for PAH using aqueous vehicle and phthalic acid using LP dispersion medium, there were no significant increases in IL-8 release. Similarly, using LP dispersion medium, trimellitic anhydride significantly increased IL-8 release was observed.
- Narita, Kazuto,Vo, Phuc Thi Hong,Yamamoto, Kenta,Kojima, Hajime,Itagaki, Hiroshi
-
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- Synthesis and pH-dependent hydrolysis profiles of mono- and dialkyl substituted maleamic acids
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Maleamic acid derivatives as weakly acid-sensitive linkers or caging groups have been used widely in smart delivery systems. Here we report on the controlled synthetic methods to mono- and dialkyl substituted maleamic acids and their pH-dependent hydrolysis behaviors. Firstly, we studied the reaction between n-butylamine and citraconic anhydride, and found that the ratio of the two n-butyl citraconamic acid isomers (α and β) could be finely tuned by controlling the reaction temperature and time. Secondly, we investigated the effects of solvent, basic catalyst, and temperature on the reaction of n-butylamine with 2,3-dimethylmaleic anhydride, and optimized the reaction conditions to efficiently synthesize the dimethylmaleamic acids. Finally, we compared the pH-dependent hydrolysis profiles of four OEG-NH2 derived water-soluble maleamic acid derivatives. The results reveal that the number, structure, and position of the substituents on the cis-double bond exhibit a significant effect on the pH-related hydrolysis kinetics and selectivity of the maleamic acid derivatives. Interestingly, for the mono-substituted citraconamic acids (α-/β-isomer), we found that their hydrolyses are accompanied by the isomerization between the two isomers.
- Su, Shan,Du, Fu-Sheng,Li, Zi-Chen
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p. 8384 - 8392
(2017/10/19)
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- Temperature-controlled solvent-free selective synthesis of tert-butyl peresters or acids from benzyl cyanides in the presence of the TBHP/Cu(OAc)2 system
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Solvent-free room temperature synthesis of tert-butyl peresters was achieved via copper-catalyzed oxidative-coupling of benzyl cyanides with tert-butyl hydroperoxide in short reaction times. Various derivatives of tert-butyl peresters were synthesized by this pathway in good to excellent yields. Further investigation revealed that the above-mentioned protocol is effective for the synthesis of benzoic acid derivatives when the reaction is conducted at 80?°C, under the same reaction conditions.
- Hashemi,Saberi,Poorsadeghi,Niknam
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p. 7619 - 7622
(2017/02/05)
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- Structure effects of amphiphilic and non-amphiphilic quaternary ammonium salts on photodegradation of Alizarin Red-S catalyzed by titanium dioxide
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The role of surfactants such as single- and double-tailed tetraalkylammonium bromide and various non-amphiphilic tetraalkylammonium salts was investigated on the TiO2 photocatalyzed degradation of 3,4-dihydroxy-9,10-dioxo-2-anthracenesulfonic acid sodium salt (Alizarin Red-S, ARS) in an air-equilibrated alkaline medium under UV light irradiation. Absorption spectral analysis showed that the photodegradation efficiency of the dye was significantly enhanced by the addition of cationic surfactants. Two interesting findings emerged from this study: ARS was almost completely degraded at surfactant concentrations close to 1 mM (values well above the cmc in the experimental conditions); moreover, on increasing the surfactant concentration, the photocatalytic reaction became less and less efficient and significantly dependent on the surfactant headgroup size. The presence of a maximum of efficiency depending on the surfactant concentration was due to the combination of catalytic and inhibiting processes. The first one likely depended on the ability of the surfactant to improve the ARS approach to the semiconductor through the formation of cationic bilayers on the TiO2 particles; this effect made the ARS more easily oxidized by TiO2. This catalytic action of the surfactant was opposed by the increase of the micellar aggregate number in the aqueous bulk, which competes with the TiO2 sites in associating to the dye. This was supported by the results obtained with the non-amphiphilic alkylammonium bromide. In this case a higher amount of salt must be added to reach the same maximum efficiency of ARS photooxidation. This is due to the lower capability of neutralization of these salts for both the ARS and the TiO2 surface; the inhibiting effect was not evidenced anymore.
- Anastasio, Paola,Del Giacco, Tiziana,Germani, Raimondo,Spreti, Nicoletta,Tiecco, Matteo
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p. 361 - 368
(2017/01/13)
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- Metal-Free Dehomologative Oxidation of Arylacetic Acids for the Synthesis of Aryl Carboxylic Acids
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A novel I2-promoted direct conversion of arylacetic acids into aryl carboxylic acids under metal-free conditions has been described. This remarkable transformation involves decarboxylation followed by an oxidation reaction enabled just by using DMSO as the solvent as well as an oxidant. Notably, aryl carboxylic acids are isolated by simple filtration technique and obtained in good to excellent yields. This protocol is free from chromatographic purification, which makes it applicable for large-scale synthesis.
- Kalmode, Hanuman P.,Vadagaonkar, Kamlesh S.,Shinde, Suresh L.,Chaskar, Atul C.
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p. 3781 - 3786
(2017/04/11)
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- Ligand-accelerated non-directed C-H functionalization of arenes
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The directed activation of carbon-hydrogen bonds (C-H) is important in the development of synthetically useful reactions, owing to the proximity-induced reactivity and selectivity that is enabled by coordinating functional groups. Palladium-catalysed non-directed C-H activation could potentially enable further useful reactions, because it can reach more distant sites and be applied to substrates that do not contain appropriate directing groups; however, its development has faced substantial challenges associated with the lack of sufficiently active palladium catalysts. Currently used palladium catalysts are reactive only with electron-rich arenes, unless an excess of arene is used, which limits synthetic applications. Here we report a 2-pyridone ligand that binds to palladium and accelerates non-directed C-H functionalization with arene as the limiting reagent. This protocol is compatible with a broad range of aromatic substrates and we demonstrate direct functionalization of advanced synthetic intermediates, drug molecules and natural products that cannot be used in excessive quantities. We also developed C-H olefination and carboxylation protocols, demonstrating the applicability of our methodology to other transformations. The site selectivity in these transformations is governed by a combination of steric and electronic effects, with the pyridone ligand enhancing the influence of sterics on the selectivity, thus providing complementary selectivity to directed C-H functionalization.
- Wang, Peng,Verma, Pritha,Xia, Guoqin,Shi, Jun,Qiao, Jennifer X.,Tao, Shiwei,Cheng, Peter T. W.,Poss, Michael A.,Farmer, Marcus E.,Yeung, Kap-Sun,Yu, Jin-Quan
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p. 489 - 493
(2017/11/28)
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- Co-production method for methyl benzoic acid and phthalic acid
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The invention discloses a co-production method for methyl benzoic acid and phthalic acid. The co-production method comprises the following steps: (1) continuously introducing fresh dimethylbenzene, a catalyst and oxygen-containing gas into a primary oxidation reactor for a reaction to obtain a primary oxidation reaction solution containing methyl benzoic acid and an eight-carbon oxygen-contained compound; (2) carrying out continuous cooling, crystallization and filtration on the primary oxidation reaction solution to obtain filter liquor and filter cake, circulating 1-98% of the filter liquor back the primary oxidation reactor continuously, and continuous rectifying the filter cake continuously, to obtain a low-boiling point front cut fraction, distillation raffinate and a methyl benzoic acid product separately; (3) adding the remaining filter liquor in the step (2) and the obtained front cut fraction and distillation raffinate in the step (2) into a secondary oxidation reactor continuously, and meanwhile continuously introducing a Co/Mn/Br catalyst, acetic acid and oxygen-containing gas into the secondary oxidation reactor for an oxidation reaction to obtain a secondary oxidation reaction mixture; and (4) continuously cooling, crystallizing and filtrating the secondary oxidation reaction mixture to obtain a filter liquor and a phthalic acid product. The co-production method has advantages of a simple process, a low cost, a high yield, good selectivity, good economic benefits, and environmental protection.
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-
Paragraph 0102; 0103; 0114; 0117; 0119
(2016/10/07)
-
- PREPARATION METHOD OF CARBOXYLIC ACIDS OR KETONES USING OZONE, SINGLET STATE-OXYGEN ATOM OR HYDROXYL FREE RADICAL
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A preparation method of carboxylic acids or ketones using ozone, singlet state oxygen atom O(1D) or hydroxyl free radical is provided. The method includes: filling ozone, singlet state oxygen atom O(1D) and/or hydroxyl free radical to cycloalkanes or benzenes at a pre-determined temperature and a pre-determined pressure in the presence or absence of light irradiation to produce carboxylic acids or ketones. The reaction occurs at room temperature and atmospheric pressure without producing harmful side products. The preparation method is a simple, low energy consuming, and eco-friendly method.
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-
Paragraph 0040-0043; 0046
(2016/05/10)
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- Naphthalenes Oxidation by Aqueous Sodium Hypochlorite Catalyzed by Ruthenium Salts under Phase-Transfer Catalytic Conditions
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Highly effective and fast oxidation of naphthalene(s) to phthalic acid(s) under biphasic conditions using nominal catalyst loading (0.5 mol%) of ruthenium chloride, 2.5 mol% tetrabutyl ammonium bromide as phase transfer catalyst and inexpensive aqueous sodium hypochlorite (NaOCl) as reagent has developed. Recovery, regeneration and reuse of the catalytic system add its merit to green chemistry.
- Patil, Rajendra D.,Sasson, Yoel
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p. 991 - 997
(2016/04/20)
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- Preparation and photocatalytic activity of WO3-MWCNT nanocomposite for degradation of naphthalene under visible light irradiation
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In this study, a WO3-multiwalled carbon nanotube nanocomposite has been prepared for the first time by in situ liquid phase process. The prepared nanocomposite was used for photodegradation of dilute solution of naphthalene under visible light irradiation. Based on our results, comparing photocatalytic activity of WO3 nanoparticle with WO3-multiwalled carbon nanotube nanocomposite showed that the photodegradation of naphthalene is negligible by using pure WO3 nanoparticles while, composition of WO3 nanoparticles with multi walled carbon nanotubes could improve significantly their photocatalytic activity under visible light. Due to its high electrical conductivity, carbon nanotube can transfer photogenerated electron on its surface and in this way decreases electron-hole recombination rate and increases photocatalytic activity. After the reaction, the irradiated solution has been analyzed by gas chromatography and mass spectrometry techniques for identification of the naphthalene photodegradation intermediates and products. 1-Naphthol, 1,4-naphthalenedione and 1,2-benzendicarboxilic acid have been determined as intermediates and based on these intermediates a suitable mechanism for photodegradation of naphthalene was suggested.
- Farhadian, Mousa,Sangpour, Parvaneh,Hosseinzadeh, Ghader
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p. 39063 - 39073
(2016/05/24)
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- Development of an empirical kinetic model for sonocatalytic process using neodymium doped zinc oxide nanoparticles
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The degradation of Acid Blue 92 (AB92) solution was investigated using a sonocatalytic process with pure and neodymium (Nd)-doped ZnO nanoparticles. The nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The 1% Nd-doped ZnO nanoparticles demonstrated the highest sonocatalytic activity for the treatment of AB92 (10 mg/L) with a degradation efficiency (DE%) of 86.20% compared to pure ZnO (62.92%) and sonication (45.73%) after 150 min. The results reveal that the sonocatalytic degradation followed pseudo-first order kinetics. An empirical kinetic model was developed using nonlinear regression analysis to estimate the pseudo-first-order rate constant (kapp) as a function of the operational parameters, including the initial dye concentration (5-25 mg/L), doped-catalyst dosage (0.25-1 g/L), ultrasonic power (150-400 W), and dopant content (1-6% mol). The results from the kinetic model were consistent with the experimental results (R2 = 0.990). Moreover, DE% increases with addition of potassium periodate, peroxydisulfate, and hydrogen peroxide as radical enhancers by generating more free radicals. However, the addition of chloride, carbonate, sulfate, and t-butanol as radical scavengers declines DE%. Suitable reusability of the doped sonocatalyst was proven for several consecutive runs. Some of the produced intermediates were also detected by GC-MS analysis. The phytotoxicity test using Lemna minor (L. minor) plant confirmed the considerable toxicity removal of the AB92 solution after treatment process.
- Khataee, Alireza,Vahid, Behrouz,Saadi, Shabnam,Joo, Sang Woo
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p. 146 - 155
(2015/10/05)
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- Heterogeneous sono-Fenton-like process using nanostructured pyrite prepared by Ar glow discharge plasma for treatment of a textile dye
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The plasma-treated pyrite (PTP) nanostructures were prepared from natural pyrite (NP) utilizing argon plasma due to its sputtering and cleaning effects resulting in more active surface area. The NP and PTP were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) and scanning electron microscopy (SEM) methods. The performance of the PTP was greater than NP for treatment of Reactive Red 84 (RR84) by the heterogeneous sono-Fenton process. The optimum amounts of main operational parameters were obtained as PTP of 4 g/L, initial dye concentration of 10 mg/L, pH of 5, and ultrasonic power of 300 W after 120 min of reaction time. Also, the effects of enhancers, and inorganic salts and t-butanol as hydroxyl radical scavengers on the degradation efficiency were investigated. Gas chromatography-mass spectroscopy analysis (GC-MS) was applied for detection of some degradation intermediates. Environmentally friendly plasma modification of the NP, in situ production of H2O2 and OH radicals, low leached iron concentration and repeated reusability at the milder pH are the significant benefits of the PTP utilization.
- Khataee, Alireza,Gholami, Peyman,Vahid, Behrouz
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p. 213 - 225
(2015/10/19)
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- Visible-light photocatalytic activity of chitosan/polyaniline/CdS nanocomposite: Kinetic studies and artificial neural network modeling
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Chitosan/polyaniline (CS/PAni), chitosan/CdS (CS/CdS) and chitosan/polyaniline/CdS nanocomposite were synthesized and characterized using X-ray diffraction pattern analysis, FT-IR spectroscopy and scanning electronic microscopy. The adsorption performance and photocatalytic activity of CS/PAni/CdS was compared with CS/PAni and CS/CdS in the removal of Reactive Blue 19 (RB19) dye. After five cycles of experiments under visible light irradiation, CS/PAni/CdS retained high photocatalytic activity which confirmed good stability of nanocomposite. Moreover, the kinetics of decolorization was investigated and novel equation rate for dye removal was established by considering two parallel mechanisms including adsorption and surface photocatalytic degradation of dye by CS/PAni/CdS. Artificial neural network was employed to develop a model for predicting the decolorization efficiency and determining the relative importance of operational parameters. A 3-layer perceptron network with optimized 5:10:1 topology could provide adequate predictive performance (R2 = 0.983). Moreover, the photocatalytic degradation of RB19 was monitored by measuring the total organic carbon (TOC) and GC-MS analysis, enabling the evaluating the mineralization and identifying the intermediates. During 120 min of experiment, more than 80% of TOC was removed.
- Rasoulifard,Seyed Dorraji,Amani-Ghadim,Keshavarz-Babaeinezhad
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